LEARNING DIARY ON IMAGE COMPRESSION.

Am very interested on the topic of Image compression which was presented by Mr. Justine L. Ngimba and Ms Zuena Mgova on 20/04/2009 the topic was good and well understood.On top of that have learned a lot of things on Image compression and comes to realized that is good and well presentation from my colleges.

THE MEARNING OF IMAGE COMPRESSION.
Image compression is minimizing the size in bytes of a graphics file without degrading the quality of the image to an unacceptable level. The reduction in file size allows more images to be stored in a given amount of disk or memory space. It also reduces the time required for images to be sent over the Internet or downloaded from Web pages.
There are several different ways in which image files can be compressed. For Internet use, the two most common compressed graphic image formats are the JPEG format and the GIF format. The JPEG method is more often used for photographs, while the GIF method is commonly used for line art and other images in which geometric shapes are relatively simple. In other hand Image compression is the action of reducing the size of image by increasing its compactness, in image compression Data compression is the technique that is used to reduce larger data files into smaller file size.

Types of image compression.

Image compression can be lossy or lossless. Lossless compression is sometimes preferred for artificial images such as technical drawings, icons or comics. This is because lossy compression methods, especially when used at low bit rates, introduce compression artifacts. Lossless compression methods may also be preferred for high value content, such as medical imagery or image scans made for archival purposes. Lossy methods are especially suitable for natural images such as photos in applications where minor (sometimes imperceptible) loss of fidelity is acceptable to achieve a substantial reduction in bit rate.
My be let asked together why image compression? therefore what have learned from my fellow that we compress in order to make transfer of image through network faster, to saves space in storage devices, It saves time for image downloaded these are some of points that why we compress the image.

Image format.
The format of image includes:-
TIFF (Tagged Image File Format)
JPEG (Joint Photographic Experts Group)
GIF (Graphical Interchange Format)
PNG (Portable network graphics)
BMP (Bitmap)

ADVANTAGES OF IMAGE COMPRESSION.

Reduce the data storage requirements
Reduce the time for images downloaded
E-mail attachment
Web pages
Photo sharing websites

DISADVANTAGES OF IMAGE COMPRESSION.

Reduce reliability of image records
Reduction of information or bits
Time consuming.
disruption of data properties

NOTE.THIS IS VERY IMPONTANT TO KNOW IN IMAGE COMPRESSION.
In compressing an image, start from the original image since compression from compressed image leads to poor image quality.
Do not save to the new format if you think you need to still proceed in compressing and image